Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND METHOD FOR CIRCUMFERENTIALLY ALIGNING
A DOWNHOLE LATCH SUBSYSTEM
TECHNICAL FIELD OF THE INVENTION
[0001] This invention relates, in general, to equipment utilized in
conjunction with
operations performed in subterranean wells and, in particular, to a system for
circumferentially aligning a latch assembly with a latch coupling in a
subterranean well and a
method for use of same.
BACKGROUND OF THE INVENTION
[0002] Without limiting the scope of the present invention, its background
will be
described in relation to forming a window in a casing string for a
multilateral well, as an
example.
[0003] In multilateral wells, it is common practice to drill a branch
or lateral wellbore
extending laterally from an intersection with a main or parent wellbore.
Typically, once the
casing string is installed and the parent wellbore has been completed, a
deflection assembly
such as a whipstock is positioned in the casing string at the desired
intersection and then one
or more mills are deflected laterally off of the whipstock to form a window
through the
casing sidewall.
[0004] In certain installations, it is desirable to drill the lateral
wellbore in a
predetermined direction from the parent wellbore such as out of the high side
of the parent
wellbore. In such installations, it is necessary to form the window at a
predetermined
circumferential orientation relative to the parent casing. In order to
properly position and
rotationally orient the whipstock such that the window is milled in the
desired direction, a
latch assembly associated with the whipstock is anchored into and rotationally
oriented
within a latch coupling interconnected in the casing string. The latch
assembly typically
includes a plurality of spring operated latch keys, each of which having an
anchoring and
orienting profile that is received in a latch profile formed internally within
the latch coupling.
In this manner, when the latch keys of the latch assembly are operatively
engaged with the
latch profile of the latch coupling, the latch assembly and the equipment
associate therewith
are axially and circumferentially anchored and rotationally oriented in the
desired direction
within the casing string.
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[0005] It has been found, however, that in certain well installations
such as deep or
extended reach wells, rotationally securing a latch assembly within a latch
coupling may be
difficult. In typically practice, once the latch assembly is substantially on
depth, the tool
string carrying the latch assembly is slowly rotated and lowered into the
well. This operation
is intended to axially positioned the latch assembly in the latch coupling and
rotationally
align the latch assembly in the latch coupling in the desired circumferential
orientation as
indicated by a torque signal at the surface. In the aforementioned deep or
extended reach
wells, however, delay in the torque signal reaching the surface due to
torsional flexibility and
wind up of the worksting, for example, may result in over stressing the latch
keys, release of
the latch assembly from the latch coupling or other failure.
[0006] Accordingly, a need has arisen for an improved system for
circumferentially
aligning a downhole latch subsystem in a subterranean well. In addition, a
need has arisen
for such an improved system that is operable for use in deep or extended reach
wells.
Further, a need has arisen for such an improved system that does not risk over
stressing the
latch keys or releasing the latch assembly from the latch coupling during
circumferential
orientation.
SUMMARY OF THE INVENTION
[0007] The present invention disclosed herein is directed to a system
for
circumferentially aligning a downhole latch subsystem in a subterranean well.
The system of
the present invention is operable for use in deep and extended reach wells. In
addition, the
system of the present invention does not risk over stressing the latch keys or
releasing the
latch assembly from the latch coupling during circumferential orientation.
[0008] In one aspect, the present invention is directed to a system
for circumferentially
aligning a downhole latch subsystem in a wellbore. The system includes a
casing string
position in the wellbore. A latch coupling is interconnected in the casing
string and has a
latch profile. A slot subassembly is also interconnected in the casing string
and has an
axially extending slot profile. A tool string is run downhole and positioned
within the casing
string. A latch assembly is interconnected in the tool string and has a
plurality of latch keys.
An orienting subassembly is also interconnected in the tool string and has a
plurality
orienting keys. After axial alignment of the orienting subassembly with the
slot
subassembly, rotation of the orienting subassembly causes operable engagement
of at least
one orienting key with the slot profile and, thereafter, axial alignment of
the latch assembly
with the latch coupling causes operable engagement of the latch keys with the
latch profile.
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[0009] In one embodiment, the plurality of latch keys are
circumferentially distributed
about the latch assembly. In certain embodiments, each of the latch keys has
axial anchor
elements and circumferential anchor elements. In these embodiments, the
circumferential
anchor elements of each latch key may be different from the circumferential
anchor elements
of the other latch keys. In some embodiments, the plurality of orienting keys
may be axially
distributed along the orienting subassembly. In these embodiments, the
orienting keys may
become progressively circumferentially wider from the downhole end to the
uphole end of
the orienting subassembly. Also, in these embodiments, the orienting keys may
have a
tapered leading edge, a tapered trailing edge or both.
[0010] In another aspect, the present invention is directed to a system for
circumferentially aligning a downhole latch subsystem in a wellbore. The
system includes an
outer tool assembly including a latch coupling having a latch profile and a
slot subassembly
having an axially extending slot profile. An inner tool assembly is
positionable within the
outer tool assembly and includes a latch assembly having a plurality of latch
keys and an
orienting subassembly having a plurality orienting keys. After axial alignment
of the
orienting subassembly with the slot subassembly, rotation of the orienting
subassembly
causes operable engagement of at least one orienting key with the slot profile
and, thereafter,
axial alignment of the latch assembly with the latch coupling causes operable
engagement of
the latch keys with the latch profile.
[0011] In one embodiment, the latch coupling and the slot subassembly are
coupled
together. In another embodiment, the latch assembly and the orienting
subassembly are
coupled together. In certain embodiments, the inner tool assembly includes a
deflection
assembly.
[0012] In a further aspect, the present invention is directed to a
method for
circumferentially aligning a downhole latch subsystem in a wellbore. The
method includes
positioning a casing string in the wellbore, the casing string including a
latch coupling having
a latch profile and a slot subassembly having an axially extending slot
profile; running a tool
string into the casing string, the tool string including a latch assembly
having a plurality of
latch keys and an orienting subassembly having a plurality orienting keys;
axially aligning
the orienting subassembly with the slot subassembly; rotating the tool string
within the casing
string to rotate the orienting subassembly relative to the slot subassembly;
operably engaging
at least one orienting key with the slot profile; and axially aligning the
latch assembly with
the latch coupling, thereby operably engaging the latch keys with the latch
profile.
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[0013] The method may also include providing coarse circumferential
prealignment of
the latch keys with the latch profile by operably engaging at least one
orienting key with the
slot profile; axially sliding at least some of the orienting key through the
slot profile;
providing fine circumferential prealignment of the latch keys with the latch
profile and/or
axially and circumferentially anchoring the latch keys within the latch
profile.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a more complete understanding of the features and
advantages of the present
invention, reference is now made to the detailed description of the invention
along with the
accompanying figures in which corresponding numerals in the different figures
refer to
corresponding parts and in which:
[0015] Figure 1 is a schematic illustration of an offshore platform
during multilateral
wellbore construction following the operation of a system for
circumferentially aligning a
downhole latch subsystem in a subterranean well according to an embodiment of
the present
invention;
[0016] Figures 2A-2H are cross sectional views of consecutive axial
sections of a
system for circumferentially aligning a downhole latch subsystem in a
subterranean well
according to an embodiment of the present invention;
[0017] Figure 3 is a quarter sectional view of a latch coupling for
use in a system for
circumferentially aligning a downhole latch subsystem in a subterranean well
according to an
embodiment of the present invention;
[0018] Figure 4 is a cross sectional view of a slot subassembly for
use in a system for
circumferentially aligning a downhole latch subsystem in a subterranean well
according to an
embodiment of the present invention;
[0019] Figure 5 is a side view of a latch assembly for use in a system for
circumferentially aligning a downhole latch subsystem in a subterranean well
according to an
embodiment of the present invention;
[0020] Figure 6 is a cross sectional view of a latch assembly for use
in a system for
circumferentially aligning a downhole latch subsystem in a subterranean well
according to an
embodiment of the present invention;
[0021] Figures 7A-7B are side views of an orienting subassembly for
use in a system
for circumferentially aligning a downhole latch subsystem in a subterranean
well according
to an embodiment of the present invention; and
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[0022] Figures 8A-8B are cross sectional views of an orienting
subassembly for use in
a system for circumferentially aligning a downhole latch subsystem in a
subterranean well
according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] While the making and using of various embodiments of the
present invention
are discussed in detail below, it should be appreciated that the present
invention provides
many applicable inventive concepts which can be embodied in a wide variety of
specific
contexts. The specific embodiments discussed herein are merely illustrative of
specific ways
to make and use the invention, and do not delimit the scope of the present
invention.
[0024] Referring to figure 1, a system for circumferentially aligning
a downhole latch
subsystem in a subterranean well is schematically illustrated and generally
designated 10. A
semi-submersible platform 12 is centered over submerged oil and gas formation
14 located
below sea floor 16. A subsea conduit 18 extends from deck 20 of platform 12 to
wellhead
installation 22, including blowout preventers 24. Platform 12 has a hoisting
apparatus 26 and
a derrick 28 for raising and lowering pipe strings such as drill string 30. A
main wellbore 32
has been drilled through the various earth strata including formation 14. The
terms "parent"
and "main" wellbore are used herein to designate a wellbore from which another
wellbore is
drilled. It is to be noted, however, that a parent or main wellbore does not
necessarily extend
directly to the earth's surface, but could instead be a branch of yet another
wellbore. A
casing string 34 is cemented within main wellbore 32. The term "casing" is
used herein to
designate a tubular string used in a wellbore or to line a wellbore. The
casing may be of the
type known to those skilled in the art as a "liner" and may be made of any
material, such as
steel or a composite material and may be segmented or continuous, such as
coiled tubing.
[0025] Casing string 34 includes a window joint 36 interconnected therein.
In addition,
casing string 34 includes a latch coupling 38 and a slot assembly 40. Latch
coupling 38 has a
latch profile that is operably engagable with latch keys of a latch assembly
(not visible in
figure 1) such that the latch assembly may be axially anchored and
rotationally oriented in
latch coupling 38. Slot assembly 40 has a slot profile that is operably
engagable with
orienting keys of an orienting subassembly (not visible in figure 1).
Operating the orienting
subassembly such that the orienting keys operably engage the slot profile of
slot assembly 40,
prealigns the latch keys of latch assembly with the latch profile of latch
coupling 38.
Thereafter, axial shifting of the latch assembly into latch coupling 38
operably engages the
latch keys of the latch assembly with the latch profile of latch coupling 38.
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[0026] In the illustrated embodiment, when the orienting keys of the
orienting
subassembly have operably engaged the slot profile of slot assembly 40 and the
latch keys of
the latch assembly have operably engaged the latch profile of latch coupling
38, a deflection
assembly depicted as whipstock 42 is positioned in a desired circumferential
orientation
relative to window joint 36 such that a window 44 can be milled, drilled or
otherwise formed
in window joint 36 in the desired circumferential direction. As illustrated,
window joint 36 is
positioned at a desired intersection between main wellbore 32 and a branch or
lateral
wellbore 46. The terms "branch" and "lateral" wellbore are used herein to
designate a
wellbore that is drilled outwardly from its intersection with another
wellbore, such as a parent
or main wellbore. A branch or lateral wellbore may have another branch or
lateral wellbore
drilled outwardly therefrom.
[0027] Even though figure 1 depicts the system for circumferentially
aligning a
downhole latch subsystem of the present invention in a vertical section of a
main wellbore, it
should be understood by those skilled in the art that the system of the
present invention is
equally well suited for use in wellbores having other directional
configurations including
horizontal wellbores, deviated wellbores, slanted wells, lateral wells and the
like.
Accordingly, it should be understood by those skilled in the art that the use
of directional
terms such as above, below, upper, lower, upward, downward, uphole, downhole
and the like
are used in relation to the illustrative embodiments as they are depicted in
the figures, the
upward direction being toward the top of the corresponding figure and the
downward
direction being toward the bottom of the corresponding figure, the uphole
direction being
toward the surface of the well and the downhole direction being toward the toe
of the well.
[0028] Also, even though the system for circumferentially aligning a
downhole latch
subsystem of the present invention is depicted in a main wellbore having a
single lateral
wellbore extending therefrom, it should be understood by those skilled in the
art that the
system of the present invention can be used in main wellbores having multiple
lateral
wellbores each of which may utilize a system of the present invention for
positioning and
orienting a deflection assembly as each system of the present invention has a
non restrictive
inner diameter that enables non mating or non aligned latch assemblies to pass
through a
latch coupling.
[0029] Referring now to figure 2, a system for circumferentially
aligning a downhole
latch subsystem is depicted and generally designated 100. In the illustrated
embodiment, a
portion of system 100 is constructed as part of casing string 102. Casing
string 102 includes a
window joint 104 that is preferably formed from an easily millable or
drillable material such
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as aluminum. Even though window joint 104 has been described as being formed
from an
easily millable or drillable material, those skilled in the art will
understand that window joint
104 could alternatively be formed from standard casing or could have a pre-
milled window
formed therein. As illustrated, window joint 104 has a window 106 formed
therethrough.
[0030] As best seen in figure 2F, casing string 102 includes a latch
coupling 108 having
a latch profile 110. As best seen in figure 2G, casing string 102 includes a
slot subassembly
112 having a slot profile 114. Downhole thereof, casing string 102 includes
any number of
downhole tubulars, such as tubular 116, or other downhole tools. In the
illustrated
embodiment, window joint 104, latch coupling 108 and slot subassembly 112 are
depicted as
being interconnected within casing string 34 proximate one another, however,
those skilled in
the art will recognize that other tools or tubulars may alternatively be
interconnected within
casing string 102 between window joint 104, latch coupling 108 and slot
subassembly 112.
Together, latch coupling 108 and slot subassembly 112 may be referred to as an
outer tool
string that is operable to receive another tool string in the central pathway
therethrough. As
explained in further detail below, latch profile 110 preferably includes a
plurality of
circumferential alignment elements that are operable to receive latch keys of
a latch assembly
therein to locate the latch assembly in a particular circumferential
orientation and axial
position.
[0031] Disposed within casing string 102 is an inner tool string that
is operable to be
run into the outer tool string. In the illustrated embodiment, the inner tool
string includes a
deflection assembly depicted as whipstock 118 having a deflector surface 120
operable to
direct a milling or drilling tool into the sidewall of window joint 104 to
create a window 106
therethrough. Alternatively, in a completion embodiment, the deflection
assembly would be
a completion deflector operably to direct the desired completion equipment
into the branch
wellbore while allowing the desired equipment or fluid to travel in the main
wellbore.
Positioned downhole of whipstock 118, the inner tool string includes a latch
assembly 122
having a plurality of latch keys 124 that are depicted as being operably
engaged with latch
profile 110 of latch coupling 108, as best seen in figure 2F. Positioned
downhole of latch
assembly 122, the inner tool string includes an orienting subassembly 126
having a plurality
of orienting keys 128, the upper two of which are depicted as being operably
engaged with
slot profile 114 of slot subassembly 112, as best seen in figure 2G. In this
configuration
when orienting keys 128 of orienting subassembly 126 have operably engaged
slot profile
114 of slot assembly 112 and latch keys 124 of latch assembly 122 have
operably engaged
latch profile 110 of latch coupling 108, deflector surface 120 of whipstock
118 is positioned
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in the desired circumferential orientation relative to window joint 104
allowing window 106
to be milled, drilled or otherwise formed in window joint 104 in a drilling
embodiment.
[0032] Referring next to figure 3, one embodiment of a latch coupling
for use in a
system for circumferentially aligning a downhole latch subsystem of the
present invention is
depicted and generally designated 200. Latch coupling 200 is representative of
latch
coupling 108 discussed above. It is noted that each latch coupling may have a
unique latch
profile that is different from the latch profile of another latch coupling.
This enables
selective engagement with a matching or mating set of latch keys in a desired
latch assembly.
Accordingly, latch coupling 200 is described herein to illustrate the type of
elements and
combination of elements that can be used to create any number of unique latch
profiles as
contemplated by the present invention.
[0033] Latch coupling 200 has a generally tubular body 202 having an
upper connector
204 and a lower connector 206 suitable for connecting latch coupling 200 to
other tools or
tubulars via a threaded connection, a pinned connection or the like. Latch
coupling 200
includes an internal latch profile 208 including a plurality of axially spaced
apart recessed
grooves 210a-210h that extend circumferentially about the inner surface of
latch coupling
200. Preferably, recessed grooves 210a-210h extend about the entire
circumferential internal
surface of latch coupling 200. Latch profile 208 also includes an upper groove
212 having a
lower square shoulder 214 and an upper angled shoulder 216. Latch profile 208
further
includes a lower groove 218 having a lower angled shoulder 220 and an upper
angled
shoulder 222.
[0034] Latch profile 208 also has a plurality of circumferential
alignment elements
depicted as a plurality of recesses disposed within the inner surface of latch
coupling 200. In
the illustrated embodiment, there are four sets of two recesses that are
disposed in different
axial and circumferential positions or locations within the inner surface of
latch coupling 200.
For example, a first set of two recesses 224a, 224b (collectively recesses
224) are disposed
within the inner surface of latch coupling 200 at substantially the same
circumferential
positions and different axial positions. A second set of two recesses 226a,
226b (collectively
recesses 226) are disposed within the inner surface of latch coupling 200 at
substantially the
same circumferential positions and different axial positions. A third set of
two recesses 228a,
228b (collectively recesses 228) are disposed within the inner surface of
latch coupling 200 at
substantially the same circumferential positions and different axial
positions. A fourth set of
two recesses 230a, 230b (collectively recesses 230) are disposed within the
inner surface of
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latch coupling 200 at substantially the same circumferential positions and
different axial
positions.
[0035] As shown, recesses 226 are disposed within the inner surface of
latch coupling
200 at a ninety degree circumferentially interval from recesses 224. Likewise,
recesses 228
are disposed within the inner surface of latch coupling 200 at a ninety degree
circumferentially interval from recesses 226. Finally, recesses 230 are
disposed within the
inner surface of latch coupling 200 at a ninety degree circumferentially
interval from recesses
228. Preferably, recesses 224, 226, 228, 230 only partially extend
circumferentially about the
internal surface of latch coupling 200.
[0036] Latch profile 208 including the circumferential alignment elements
creates a
unique mating pattern operable to cooperate with the latch key profile
associated with a
desired latch assembly to axially and circumferentially anchor and orient, for
example, a
whipstock assembly in a particular desired circumferential orientation
relative to the latch
coupling. The specific profile of each latch coupling can be created by
varying one or more
of the elements or parameters thereof For example, the thickness, number and
relative
spacing of the recesses can be altered.
[0037] Referring next to figure 4, one embodiment of a slot
subassembly for use in a
system for circumferentially aligning a downhole latch subsystem of the
present invention is
depicted and generally designated 250. Slot subassembly 250 has a generally
tubular body
252 including an upper connector 254 and a lower connector 256 suitable for
connecting slot
subassembly 250 to other tools or tubulars via a threaded connection, a pinned
connection or
the like. Slot subassembly 250 includes an axially extending internal slot
profile 258. In the
illustrated embodiment, slot profile 258 includes a tapered upper entry 260
and tapered lower
entry 262. Preferably, the circumferentially width of slot profile 258 will
substantially match
that of the widest orienting key as described in greater detail hereinbelow.
The length of slot
profile 258 is preferably at least long enough such that at least one of the
orienting keys
remains within slot profile 258 during alignment operations as described in
greater detail
hereinbelow.
[0038] Referring next to figures 5-6, one embodiment of a latch
assembly for use in a
system for circumferentially aligning a downhole latch subsystem of the
present invention is
depicted and generally designated 300. Latch assembly 300 has an outer housing
302
including an upper housing 304 having an upper connector 306 suitable for
coupling latch
assembly 300 to other tools or tubulars via a threaded connection, a pinned
connection or the
like. Outer housing 302 includes a key housing 308 having four
circumferentially
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distributed, axially extending key windows 310. Outer housing 302 also
including a lower
housing 312 having a lower connector 314 suitable for coupling latch assembly
300 to other
tools or tubulars via a threaded connection, a pinned connection or the like.
Disposed within
key housing 308 is a plurality of spring operated latch keys 316 that are
operable to partially
extend through key windows 310. Latch keys 316 are radially outwardly biased
by upper and
lower Belleville springs 318, 320 that urge upper and lower conical wedges
322, 324 under
latch keys 316.
[0039] Each of the latch keys 316 has a unique key profile, such as
key profile 326, that
enables the anchoring and orienting functions of latch assembly 300 with a
mating latch
coupling having the appropriate latch profile. As illustrated, key profile 326
includes a
plurality of radial variations that must correspond with mating radial
portions of a latch
profile in order for a latch key 316 to operably engage with or snap into that
latch profile. In
order for each of the latch keys 316 to operably engage with a latch profile,
the latch
assembly 300 must be properly axially positioned within the mating latch
coupling and
properly circumferentially oriented within the mating latch coupling. For
example, key
profile 326 may mate with the portion of latch profile 208 having recesses
230, described
above. In this manner, the axial location and circumferential orientation of a
device, such as
a deflection assembly, that is coupled to or operably associated with latch
assembly 300 can
be established.
[0040] Referring next to figures 7A-8B, one embodiment of an orienting
subassembly
for use in a system for circumferentially aligning a downhole latch subsystem
of the present
invention is depicted and generally designated 350. Orienting subassembly 350
has an outer
housing 352 including an upper connector 354 suitable for coupling orienting
subassembly
350 to other tools or tubulars via a threaded connection, a pinned connection
or the like.
Outer housing 352 includes an upper key housing 356 having a key window 358, a
middle
key housing 360 having a key window 362 and three lower key housings 364, 368,
372
having, respectively, key windows 366, 370, 374. Outer housing 352 also
including a lower
connector 376 suitable for coupling orienting subassembly 350 to other tools
or tubulars via a
threaded connection, a pinned connection or the like.
[0041] Operably associated with upper key housing 356 is a spring operated
orienting
key 378 that is operable to partially extend through key window 358. Orienting
key 378 is
radially outwardly biased by a plurality of springs 380 disposed between upper
key housing
356 and orienting key 378. Operably associated with middle key housing 360 is
a spring
operated orienting key 382 that is operable to partially extend through key
window 362.
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Orienting key 382 is radially outwardly biased by a plurality of springs 384
disposed between
middle key housing 360 and orienting key 382. Operably associated with lower
key housing
364 is a spring operated orienting key 386 that is operable to partially
extend through key
window 366. Orienting key 386 is radially outwardly biased by a plurality of
springs 388
disposed between lower key housing 364 and orienting key 386. Operably
associated with
lower key housing 368 is a spring operated orienting key 390 that is operable
to partially
extend through key window 370. Orienting key 390 is radially outwardly biased
by a
plurality of springs 392 disposed between lower key housing 368 and orienting
key 390.
Operably associated with lower key housing 372 is a spring operated orienting
key 394 that is
operable to partially extend through key window 374. Orienting key 394 is
radially
outwardly biased by a plurality of springs 396 disposed between lower key
housing 372 and
orienting key 394.
[0042] In the illustrated embodiment, each of the lower orienting keys
386, 390, 394
has a first circumferential width, middle orienting key 382 has a second
circumferential width
and upper orienting key 378 has a third circumferential width. The first
circumferential
width is less than the second circumferential width and the second
circumferential width is
less than the third circumferential width. In this manner, the width of the
orienting keys
becomes progressively larger from lower orienting keys 386, 390, 394 to upper
orienting key
378. The benefit of this configuration will be described hereinbelow. In
addition, each of
the orienting keys 378, 382, 386, 390, 394 has a tapered leading and trailing
edge, the benefit
of which will be described hereinbelow.
[0043] The operation of a system for circumferentially aligning a
downhole latch
subsystem of the present invention will now be described. An outer tool string
including a
window joint, a latch coupling and a slot subassembly are interconnected in a
casing string
and the casing string is run into, for example, the main wellbore. Following
completion, if
desired, of any zones downhole of the window joint, an inner tool string
including a
deflection assembly, a latch assembly and an orienting subassembly is run into
the casing
string. Preferably, the orienting keys of the orienting subassembly are
circumferentially
aligned with a specific and known latch key of the latch assembly such as the
first latch key
of the latch assembly. The inner tool string is moved downhole via a
conveyance such as a
jointed tubing string until the latch assembly is on depth with the latch
coupling. This
operation is indicated by a weight signal on the surface. The inner tool
string is then picked
up a predetermined distance such that at least one of the lower orienting keys
is axially
aligned with the slot profile of the slot subassembly. In this configuration,
the inner tool
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string is rotated within the casing string to rotate the orienting subassembly
relative to the slot
subassembly until at least one lower orienting key operably engages or snaps
into the slot
profile.
[0044] As described above, as the lower orienting keys have a
relatively narrow
circumferential width, the at least one lower orienting key axially aligned
with the slot profile
easily enters the slot profile without interference with the sides of the slot
profile even as the
inner tool string is rotated. Once at least one of the lower orienting key has
operably engaged
the slot profile, a torque signal is received at the surface. Due to the
relatively long axial
length of the orienting keys, the allowable torque between the orienting key
or keys of the
orienting subassembly and the slot profile of the slot subassembly is much
greater than the
previously allowable torque between the latch keys of a latch assembly and the
latch profile
of a latch coupling. As such, the risk of over stressing the latch keys or
releasing the latch
assembly from the latch coupling during circumferential orientation is
alleviated.
[0045] When at least one of the lower orienting key has operably
engaged the slot
profile, coarse circumferential prealignment of the latch keys with the latch
profile is
achieved and the inner tool string may be moved downhole. As this downhole
movement
occurs, the middle orienting key enters the slot profile. As the middle
orienting key has a
circumferential width greater than that of the lower orienting keys, improved
circumferential
prealignment of the latch keys with the latch profile is achieved. As further
downhole
movement occurs, the upper orienting key enters the slot profile. As the upper
orienting key
has a circumferential width greater than that of the middle orienting keys,
fine
circumferential prealignment of the latch keys with the latch profile is
achieved. The tapered
leading and trailing edges of the orienting keys as well as the tapered upper
entry and lower
entry of the slot profile aid in the axial movement of the orienting keys
through the slot
profile.
[0046] Further downhole movement of the inner tool string within the
outer tools string
axially aligns the latch assembly with the latch coupling. Due to the
circumferential
prealignment of the latch keys with the latch profile and particularly the
fine circumferential
prealignment of the latch keys with the latch profile achieved by the upper
orienting key in
the slot profile, the latch keys operably engage the latch profile with little
or no rotation of
the inner tool string. In this configuration, the latch keys axially and
circumferentially anchor
the latch assembly within the latch coupling. Alternatively, the latch keys
may axially anchor
the latch assembly within the latch coupling while the upper orienting key in
the slot profile
may provide circumferential anchoring. In either case, when the latch keys of
the latch
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PCT/US2012/059308
assembly have operably engaged the latch profile of the latch coupling, the
deflection
assembly is positioned in a desired circumferential orientation relative to
the window joint
such that a window can be milled, drilled or otherwise formed in window joint
in the desired
circumferential direction.
[0047] While this invention has been described with reference to
illustrative
embodiments, this description is not intended to be construed in a limiting
sense. Various
modifications and combinations of the illustrative embodiments as well as
other
embodiments of the invention will be apparent to persons skilled in the art
upon reference to
the description. It is, therefore, intended that the appended claims encompass
any such
modifications or embodiments.
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